Biology subjects

Lippman, Z. B.

Publications and source records attributed to Lippman, Z. B..

8 recordsLinked to original sources

bioRxiv2026

A neofunctionalized flowering antagonist created an evolutionary contingency that channeled Solanaceae adaptation

Neofunctionalization is a rare fate of gene duplication, classically defined as the acquisition of novel functions that potentiate the emergence of new traits. Rather than evolving to function autonomously, neofunctionalized genes may also remain embedded within their ancestral regulatory networks, potentially reshaping the genetic trajectories through which phenotypic change occurs. Testing this hypothesis, we leveraged a pan-genetic platform comprising ten Solanaceae species and show that a paralog of the flowering hormone florigen neofunctionalized into a flowering antagonist and was repeatedly selected during crop domestication and adaptation of wild plants across 50 million years of evolution. Independent selection of cis-regulatory and coding mutations in SELF-PRUNING 5G (SP5G) enabled rapid flowering in the wild ancestor of domesticated tomato from Central America as well as major and indigenous eggplant crop lineages domesticated in Asia and Africa. We further found that cis-regulatory sequence changes reduced SP5G expression and flowering time in wild species native to distinct environments in the Americas and Australia, relationships that we validated by genome editing. Together with similar patterns observed across diverse species and developmental networks, we propose that antagonistic neofunctionalized paralogs create evolutionary contingencies that channel adaptive trajectories across plant lineages.

plant biology↗

bioRxiv2025

A deep-time landscape of plant cis-regulatory sequence evolution

Developmental gene function is often conserved over deep time, but cis-regulatory sequence conservation is difficult to identify. Rapid sequence turnover, paleopolyploidy, structural variation, and limited phylogenomic sampling have impeded conserved non-coding sequence (CNS) discovery. Using Conservatory, an algorithm that leverages microsynteny and iterative alignments to map CNS-gene associations over evolution, we uncovered [~]2.3 million CNSs, including over 3,000 predating angiosperms, from 284 plant species spanning 300 million years of diversification. Ancient CNSs were enriched near developmental regulators, and mutating CNSs near HOMEOBOX genes produced strong phenotypes. Tracing CNS evolution uncovered key principles: CNS spacing varies, but order is conserved; genomic rearrangements form new CNS-gene associations; and ancient CNSs are preferentially retained among paralogs, but are often lost as cohorts or evolve into lineage-specific CNSs. One Sentence SummaryConservatory maps ancient cis-regulatory elements and uncovers regulatory evolution dynamics.

plant biology↗

bioRxiv2025

Effect of plant tissue culture parameters on the ploidy level of Physalis grisea, Solanum lycopersicum, and Solanum prinophyllum regenerants

Plants regenerated from seedling explants (hypocotyls and cotyledons) of the Solanaceae family members Physalis grisea (groundcherry), Solanum lycopersicum (tomato), and Solanum prinophyllum (forest nightshade) were used to determine the in vitro culture parameters that contribute to the incidence in polyploidization of tissue culture-derived plants (regenerants) from these species. We examined the possible effects of zeatin concentration in the plant regeneration medium, explant source, and species. Plants were grown to maturity under greenhouse conditions, pollen was collected and germinated. Flow cytometry analysis verified the utility of the pollen germination method for determining differences in ploidy, which was based on the number of pollen tubes produced with one tube representing diploid and two indicating polyploid. As for zeatin concentration, we assessed the effect of our standard method of initiation on medium containing 2 mg/l followed by 1 mg/l 2 weeks after culture initiation in comparison with 0.25, 0.5, and 1 mg/l throughout the culture lifetime. There were no major correlations for zeatin concentration on ploidy status across the species except for plants regenerated from S. lycopersicum hypocotyl explants where the percentage of polyploid regenerants increased with increasing concentrations. As for species and explant effects, P. grisea plants regenerated from hypocotyl explants had the highest percentage of polyploid plants at 81% compared to 43% and 35% for S. lycopersicum and S. prinophyllum, respectively. From cotyledons, 8% of S. lycopersicum and 20% of S. prinophyllum were polyploid. A comparison with P. grisea could not be made because cotyledon explants do not regenerate on zeatin-containing medium. The results indicated the incidence of polyploidization cannot be generalized for zeatin concentration, however, an influence of explant type and species was observed. Effects of increased ploidy on plant morphology were primarily larger flower and seed size; however, no significant differences were observed in plant or fruit size.

plant biology↗

bioRxiv2024

Solanum pan-genomics and pan-genetics reveal paralogs as contingencies in crop engineering

Pan-genomics and genome editing technologies are revolutionizing the breeding of globally cultivated crops. A transformative opportunity lies in the reciprocal exchange of genotype-to-phenotype knowledge of agricultural traits between these major crops and hundreds of locally cultivated indigenous crops, thereby enhancing the diversity and resilience of our food system. However, species-specific genetic variants and their interactions with desired natural or engineered mutations pose barriers to achieving predictable phenotypic effects, even between closely related crops or genotypes. Here, by establishing a pan-genome of the crop-rich genus Solanum and integrating functional genomics and genetics, we show that gene duplication and subsequent paralog diversification are a major obstacle to genotype-phenotype predictability. Despite broad conservation of gene macrosynteny among chromosome-scale references for 22 species, including 13 indigenous crops, hundreds of global and lineage-specific gene duplications exhibited dynamic evolutionary trajectories in paralog sequence, expression, and function, including among members of key domestication gene families. Extending our pan-genome with 10 cultivars of African eggplant and leveraging quantitative genetics and genome editing, we uncovered an intricate history of paralog emergence and evolution within this indigenous crop. The loss of an ancient redundant paralog of the classical regulator of stem cell proliferation and fruit organ number, CLAVATA3 (CLV3), was compensated by a lineage-specific tandem duplication. Subsequent pseudogenization of the derived copy followed by a cultivar-specific structural variant resulted in a single fused functional copy of CLV3 that modifies locule number alongside a newly identified gene controlling the same trait. Our findings demonstrate that paralog diversifications over short evolutionary periods are critical yet underexplored contingencies in trait evolvability and independent crop domestication histories. Unraveling these contingencies is crucial for translating genotype-to-phenotype relationships across related species.

genetics↗

bioRxiv2024

Convergent evolution of plant prickles is drivenby repeated gene co-option over deep time

An enduring question in evolutionary biology concerns the degree to which episodes of convergent trait evolution depend on the same genetic programs, particularly over long timescales. Here we genetically dissected repeated origins and losses of prickles, sharp epidermal projections, that convergently evolved in numerous plant lineages. Mutations in a cytokinin hormone biosynthetic gene caused at least 16 independent losses of prickles in eggplants and wild relatives in the genus Solanum. Strikingly, homologs promote prickle formation across angiosperms that collectively diverged over 150 million years ago. By developing new Solanum genetic systems, we leveraged this discovery to eliminate prickles in a wild species and an indigenously foraged berry. Our findings implicate a shared hormone-activation genetic program underlying evolutionarily widespread and recurrent instances of plant morphological innovation.

evolutionary biology↗

bioRxiv2021

Automated assembly scaffolding elevates a new tomato system for high-throughput genome editing

Advancing crop genomics requires efficient genetic systems enabled by high-quality personalized genome assemblies. Here, we introduce RagTag, a toolset for automating assembly scaffolding and patching, and we establish chromosome-scale reference genomes for the widely used tomato genotype M82 along with Sweet-100, a rapid-cycling genotype that we developed to accelerate functional genomics and genome editing. This work outlines strategies to rapidly expand genetic systems and genomic resources in other plant species.

plant biology↗

bioRxiv2020

SVCollector: Optimized sample selection for cost-efficient long-read population sequencing

An increasingly important scenario in population genetics is when a large cohort has been genotyped using a low-resolution approach (e.g. microarrays, exome capture, short-read WGS), from which a few individuals are selected for resequencing using a more comprehensive approach, especially long-read sequencing. The subset of individuals selected should ensure that the captured genetic diversity is fully representative and includes variants across all subpopulations. For example, human variation has historically been focused on individuals with European ancestry, but this represents a small fraction of the overall diversity. To address this goal, SVCollector (https://github.com/fritzsedlazeck/SVCollector) identifies the optimal subset of individuals for resequencing. SVCollector analyzes a population-level VCF file from a low resolution genotyping study. It then computes a ranked list of samples that maximizes the total number of variants present from a subset of a given size. To solve this optimization problem, SVCollector implements a fast greedy heuristic and an exact algorithm using integer linear programming. We apply SVCollector on simulated data, 2504 human genomes from the 1000 Genomes Project, and 3024 genomes from the 3K Rice Genomes Project and show the rankings it computes are more representative than widely used naive strategies. Notably, we show that when selecting an optimal subset of 100 samples in these two cohorts, SV-Collector identifies individuals from every subpopulation while naive methods yield an unbalanced selection. Finally, we show the number of variants present in cohorts of different sizes selected using this approach follows a power-law distribution that is naturally related to the population genetic concept of the allele frequency spectrum, allowing us to estimate the diversity present with increasing numbers of samples.

bioinformatics↗

bioRxiv2019

Fast and accurate reference-guided scaffolding of draft genomes

BackgroundAs the number of new genome assemblies continues to grow, there is increasing demand for methods to coalesce contigs from draft assemblies into pseudomolecules. Most current methods use genetic maps, optical maps, chromatin conformation (Hi-C), or other long-range linking data, however these data are expensive and analysis methods often fail to accurately order and orient a high percentage of assembly contigs. Other approaches utilize alignments to a reference genome for ordering and orienting, however these tools rely on slow aligners and are not robust to repetitive contigs.\n\nResultsWe present RaGOO, an open-source reference-guided contig ordering and orienting tool that leverages the speed and sensitivity of Minimap2 to accurately achieve chromosome-scale assemblies in just minutes. With the pseudomolecules constructed, RaGOO identifies structural variants, including those spanning sequencing gaps that are not reported by alternative methods. We show that RaGOO accurately orders and orients contigs into nearly complete chromosomes based on de novo assemblies of Oxford Nanopore long-read sequencing from three wild and domesticated tomato genotypes, including the widely used M82 reference cultivar. We then demonstrate the scalability and utility of RaGOO with a pan-genome analysis of 103 Arabidopsis thaliana accessions by examining the structural variants detected in the newly assembled pseudomolecules. RaGOO is available open-source with an MIT license at https://github.com/malonge/RaGOO.\n\nConclusionsWe demonstrate that with a highly contiguous assembly and a structurally accurate reference genome, reference-guided scaffolding with RaGOO outperforms error-prone reference-free methods and enable rapid pan-genome analysis.

bioinformatics↗